Apparatus for drying



Noy. 21, 1944. w. S;I'RQBRIDGE- APPARATUS FOR DRYING Filed Jan. 13, 19428 Sheets-Shegt l INVENTOR Wz'lZim/z \btrobr idye A1 ATTORNEY? N v-21,wsmBRml-z 2,363,4 7

APPARATUS FOR DRYING Filed Jan. 13, 1942 8 Sheets-Sheet 2 INVENTORWilda/n b' frobriaye Nov.'2l, 1944. WATROB LDGE 2,363,467

7 APPARATUS FOR DRYING Filed Jan. 13, 1942 Y 8 Sheets-Sheet 3 4 INVENTOR-,Wlliam s il'obridje ATTORNEYS Nov. 21, 1944.

W. STROBRIDGE I APPARATUS FOR DRYING Filed Jan. 13. 1942 S SheetS-She'et4 e 0 1 m Y mh .m

Nov; 21, 1944. 'w STROBRIDGE v 2,363,467

' APPARATUS FOR DRYING Filed Jan. 15, 1942 sheetsshee't lNVENTOR William5' il'obrp'd je r. $512M v/o gwmj ATTORNEY Nov. 21, 1944. w. STROBRIDGE2,363,467

APPARATUS FOR DRYING Filed Jan. 13, 1942 8 Sheets-Sheet 6 INVENTOR Billiant fitrobrz'a 6 Nov. 21,1944. $TR0'B R|DGE 2,363,467

APPARATUS FOR DRYING Filed Jan. '13, 1942 8 Sheets-Sheet 7 INVENTORWilliam fiil'ofu'id e ATTORNEYS W. STROBRIDGE APPARATUS FQR DRYING Nov.21, 1944.

Filed Jan. 13, 1942 8 Sheet s-Sheet 8 injury to the Patented Nov. 21,1944 PATENT OFFICE 2,363,467 APPARATUS FOR DRYING William Strobridge,Syracuse, N. Y., assignor to United States Hofiman MachineryCorporation,

New York, N. Y., a corporation of Delaware Application January 13, 1942,Serial No. 426,570

. Claims. This invention relates to apparatus employed in dry cleaning,and more particularly to apparatus for drying materials which havepreviously been treated with an inflammable cleaning solvent. Suchapparatus forms of U. S. Patent 2,203,422 fssued'June 4, 1940, and U. S.Patent 2,217,153 issued October 8, 1940. Patent 2,203,422 discloses adrying tumbler in which the materials to be dried are first subjected tothe flow of air maintained at a safe maximum temperature relative to theflash-point of the solvent used, for a predetermined interval rf timefor the removal of the greater part of the solvent, then subjected to aflow of air at a temperature considerably point for anotherpredetermined interval of time, and finally subjected again to a flow ofair at a safe temperature relative to the flash-point, to cool andcomplete deodorization of the materials and to down to a point where thecycle of operation might immediately be repeated with safety. In thatapparatus air is drawn then through a rotating clothes containingcylinder by means of an electrically driven fair which discharges thesolvent laden air to the atmosphere outside the tumbler. 'Toinsure safeoperation, certain relays and .interlocks areprovided to make itimposs'ble td "start rotation of the tumbler drum unless the inoperaiton by connecting the fan motor to acurrent source, and provisionis made for automatically spraying the interior of the tumbler withsteam and/or sounding a steam whistle in the event of current failure tothe fan during op- --eration of -the tumbler.

It is an object of the present invention-to provide improved apparatusof the forth.

. To this end the electrically driven fan has 10 v been replaced by afan driven by a steam turbine so that in the event of current failurethere would still be a circulation of air through the tumbler, and anytendency to generate a flammable vapor-air mixture would be obviated.This avoid the necessity of sounding a whistle orinjecting steam intothe tumbler to prevent explosion'or goods within the tumbler drum.

In order to make emc'ient useof'the exhaust steam from the turbine, thisis utilized in a primary heater which remains in operation throughoutthe entire drying cycle. This exhaust steam is the sole source of heatduring the low heat and cooling periods of operation of the tumbler,

and is controlled to maintain the air at the max 5 heater i1. Each thesubject matter 5 higher than the flash- 15 bring the temperature withinthe dryer go through a heater.

fan has first been t 30 apparatus and character set imum temperature forthose periods. The air issuing from the primary-heater passes through asecondary heater which, during the high heat period of the cycle, issupplied with live steam to heat the air supply the flash-point of thesolvent.

Other objects will be in part obvious and in' part pointed outhereinafter.

The invention accordingly consists in the features of construction,combinations of elements,

and-arrangements of parts as will be exemplified in the structureto behereinafter described and the scope of the application of which will beindicated in the following claims.

In 1 the accompanying drawings in which s shown" one of the variouspossible embodiments of my invention- Fig. 1 is a front elevation of atumbler emb dying. features of the present invention;

Fig.2 is a right side elevation thereof;

Fig. 3 is a left side elevation thereof;

Fig. 4 is arear elevation thereof;

Fig. 5. is a cross-section on line Fig. 6 is a top plan view of the rearportion of the operating and control devices;

top andright and rear sidesof thetumbler;

Fig.-f8 is a wiring diagram devices shown figures. 7. I

Simflar reference characters refer to'similar parts-throughout thevarious views of the drawings. I

Description of apparatus for a general conception of the preferred'formof apparat There is disclosed a tumbler coniprising'a The drum H issurrounded by an internal cylin- -drical shell 9'2 which encloses thedrum for approximately three-quarters of the periphery thereof, thehinged outer shell door It at the front of the tumbler housingcompleting the enclosure. To the rear of the drum chamber near I the topof the casing l0 there is provided a-coil box It extending rearwardiythrough and beyond the rear plate of the casing and connecting with theatmosphere by means of an opening l5.

' The heater 7 Coil box M contains two heater units com? prising aprimary heater l6 and a secondary of these heaters preferably is to thedesired point above 5--5-of Fig, 4;

the tumbler showing. the location of certain of;

pertaining to the ezv e Reference to Figs. '1 to s inclusive may be had'titer shell or casing l0 having rotatably mounted therein a forami'nousdrumil.

. the inlet of the of the fin type wherein the heat from the steamheating coils is radiated by suitable fins which.

surround the coils and provide a plurality of narrow passages for theflow of air, as indicated at l8 in Fig. 4. The primary and secondaryheaters I 6 and I! are heated respectively by steam coils I9 and 20. Theheater units are slightly spaced apart, as indicated at 2! in Fig. 5, toprovide a temperature measuring chamber, the purpose of which will beexplained hereinafter.

Air from the secondary heater i1 is led to the.

top of the tumbler and admitted to the drum ll through an opening 22 inthe inner shell I2. The air outlet from the drum chamber is through anopening 23 at the bottom of the shell l2, opposite the opening 22. Theair thus passes into the lower part of the tumbler casing beneath thedrum chamber, where there is located an exhauster. fan 24 having an airinlet 25 and outlet 21, the latter projecting through the rear wall ofthe casing. The fan is driven, in the present.

be referred to in connection with the wiring dia-.

gram and the description of the operation of the tumbler.

Steam piping The steam piping to the, coils l8 and may best beunderstood by reference to. Fig. 7. The

steam line dropping down from abovepasses through a manually operatedmain shut-off valve 3| and then on below to a T 32. Below the T thismain line goes to the upturned opening of a T 33, and then continuesdown from the said T to the inlet 34 of the steam turbine 28. From theoutlet 35 of the turbine an exhaust steam line connects with a 1- n andthen discharges through a. suitable back pressure valve 31 to theatmosphere, or, if desired, to the heating system of the building inwhich the tumbler is located. The side outlet of the T 33 is connectedto a hand operated valve which connects with a steam spray pipe 4|located inwardly of the secondary heater I! in the air passage leadingto the tumbler drum.

From the T 32 a live steam line connects through the lever operatedvalve 38 directly with secondary heater coil 20. From the T 38 in theturbine exhaust line. a low pressure steam line runs through thethermostatically operated valve 43 to the inlet of coil IS. Thethermostatic valve 43 is controlled in its operation by a bulb 44located between the primary and secondary heaters in the chamber 2 l.

The outlet pipe 46 of the high pressure coil 20 passes through a swingcheck valve 41 and a high pressure steam trap 48 to any suitable returnpipeof the steam heating system. A by-pass in this line contains asuitable thermostatic air venting valve 49. The outlet pipe 46' of thelow pressure coil i9 is similarly equipped with a w pressure steam traswing check valve 41, a and an air venting v ve 49'.

Steam valve 38 in the live steam line to the secondary heater coil 20 isoperated automatithe primary heater to the bulb 44. Thus the operationof the valve 43 is controlled by the temperature of the air in thetemperature measuring chamber 2| after the air has passed through theprimary heater but before the temperature of the air has been influencedby the high pressure secondary heater.

Cylinder drive The tumbler drum shaft II is joumaled in bearings 5|mounted on brackets 52 secured to the sidexplates of the tumblerhousing. Upon the shaft II is mounted a spur gear 53 driven by a pinion54 mounted upon a jack shaft 55- 5' forming part of a pulley and beltshifting header assembly, as best seen in Figs. 1, 3 and 4, in which thejack shaft 55 is shown to be rotatably mounted in a pair of bearings 56,51 carried by a header bracket or arm 58. This bracket is bolted to thesideof the tumbler housing. The jack shaft 55 carries a tight pulley 59and a pair of loose pulleys 60, 6|. Also loosely mounted upon the shaft55 is a header worm 82 which has a pinand-slot connection, not shown,with the hub of the loose pulley 6| so as to be driven thereby.

Mounted upon the header bracket 58 in c0 axial relation to the shaft 55is a header arm assembly comprising the support 63, to which ispivotally connected the belt shifter fork 64. The header arm assemblyincludes a worm gear 61- on support 83 meshing with the worm 62, and areciprocating slide shaft 88 slidably and rotatably mounted at the upperend of the support 83 in a block 89. Projecting from the block 69 paraguide rod 18. A weighted pin or header-fall ll secured to and extending68 shifts with j allel to the shaft 68 is at right angles to the slideshaft the slide shaft about its axis so that the pin H may engage theupper end of the shifter fork 64 when the pin H is swung in onedirection to a orizontal position and, sliding along the upper ace ofthe shifter fork, eventually settle in the notch 12 formed in the upperend of the shifter fork. When swung in the opposite direction to ahorizontal positio the pin H will be free of the shifter fork 84 butwill engage one or the other of the beveled surfaces 13 on the block 69and ride down to a neutral position.

Mounted loosely upon the slide shaft 68 in a position between the block69 and the tumbler housing is s held against endwise movement upon theslide shaft in any suitable manner.. The sleeve carries a forked arm 16cooperating with the guide 2 provided with belt guide blocks I8 and 19,each equipped with a belt guide are so disposed that when the shifterpin 1| occupies its center or neutral position, the two drive belts 8|,82 will be positioned upon the loose pulleys so that under theseconditions no power will be transmitted to the tumbler drum. It will benoted that the belt 8| crossed whereby the shifting of one shiftersleeve I4. This sleeve is 80. The belt guides the belt 82 is direct andbelt of! and the other belt on to the tight pulley will effect areversal ofthe rotation of the tumbler drum. It will be understood that.belts 8| and 82 connect with a suitable line shaft, not shown, and areof a. width to enable them to drive the tight pulley without disengagingtheir respective loose pulleys.

The operation of the header .assembly will now be briefly described, Itwill be noted that since the worm 62 is driven by the loose pulley 6|,it will always rotate in the same direction irrespective of the locationof the belts with respect to the tight pulley. Thus, also, the wormwheel 61 will rotate constantly in one direction. This wheel drives acrank pin 83 slidable up and down shift the drive belts and reverseoperation of the tumbler drum. For a fuller description of this headerconstruction, referencemay be made to the above mentioned Patent No.2,203,422.

Mechanically controlled mechanism Referring again to the drawings,mechanical means for setting the tumbler in operation to begin thedrying cycle will now be described.

' bracket I85 which is secured to the fixed bracket by means of boltswhich pass through arcuate slots in the fixed bracket whereby theadjust- In the position of the parts shown in Fig. 3, the

condition of the apparatus is that which would obtain after 'a batch ofmaterial has been placed in the drum and the shell door closed. Underthese conditions the'shell door cannot be reopened or the header-fallbrought into engagement with the shifter fork to start rotation of thedrum until after the exhauster fan has been started, to make certainthat there is an active flow of air through the tumbler. It may occur,at the start of a day's work, that the door will be closed and locked inthe position shown in Fig. 3, when, as will be shown hereinafter, itwill be necessary first to set in operation the steam turbine driven fanbefore it is possible toopen the shell door for the loading of the drum.But if the door should be 'open prior to starting the fan, the drum maybe loaded and thereafter the door closed, but no further operationcanthen take place until the fan has been "started.

The means for shifting the header-fall into or out-of engagement tocause belt drive of the tight pulley on the jack shaft comprises anoperating lever 89 which with other operating parts is mounted upon acast bed-plate 98 bolted'to the side sheet of the tumbler housing.Operating lever 89 is pinned to a shaft 9| rotatable in a bearingvforming part of said bedplate casting. Attached to one end of theoperating lever is a roller 92 adapted, when the lever 89 is thrown toengage the belt shifting header-fall in operating position, to come incontact with a switch operating arm 93, moving said arm to shift aswitch A to initiate the opable bracket may be adjusted radially aboutthe header jack shaft 55. The adjustable bracket I05 is provided with aseat for the pin'I08, and also with a bearing I86 for the extruded hub I01 of a pinion I08. This pinion meshes with the gear segment 99 mounted,as described, upon the pin I88. Extruded hub I01 of pinion I08 isprevented .from endwise movement by means of a set collar 0 and isprovided with a coaxial bore, not shown; through which the reciprocatingshaft 68 is free to move. Portions of this extruded hub diametricallyopposite each other are removedto form long slots III, providing drivingsurfaces against a pin through the shaft 68. Thus when the gear segment99 is moved by endwise shifting of the link 98', the resulting movementof pinion I08 and its extruded hub rotates shaft 68 by means of the pinII 2, no matter at what point in its path of travelthis pin is located.For a clearer disclosure of this structure, reference may be had toaforesaid Patent 2,203,422.

This movement accomplishes the 180 throw of the l eader-fall II and isthe means for initiating or terminating association of the tight pulley59 with one or the other of the driving belts 8|, 82 and thus therotation of the tumbler cylinder. It will be understood then'that. whenthe operating lever 89 is thrown toward the center of the tumbler awayfrom the position shown in Fig. 3. the toggle composed of the members94, 95 straightens out and causes rotation of the interlocking member 96about its axis of rotation, causing the arm 96 to move and rock the gearsegment 99 toward the front of the tumbler. The straightening of thetoggle94, 95 locks the operating lever in .the engaged position of. thebelt shifter header,

thus insuring that the tumbler drive will continue until the startinglever 89 is returned to its forward or disengaged position.

Safety devices associated with mechanical control mechanism the openingof the shell door I3 when the belt shifter header is engaged and alsopreventing any actuation of the operating mechanism to start rotation ofthe drum when the shell door is open.

Referring to Fig. 3. it will be seen that the interlocking member96 isprovided with thepro- 'jection 96', as mentioned above, which serves toeration of certain automatic controls, as will be explained hereinafter.

Pinned to the shaft 9| in proper angular relation to the lever 89 is anarm 94, connected form an interlock between the operating lever 89 andthe shell door I3. This projection cooperates with a camlike abutmentmember I23 mounted to move about the axis of the shell door I3. With thelever 89 in the header disengaged position. as shown in Fig. 3, there isno obstruction to the openin and closing of the door I3 due to theprojection 96', but it will? be understood I I2 fastened that whenthe'door is' open a portion of the abutment I23 lies in the path ofprojection 96, so that the operating lever cannot be thrown from thedisengaged position to the engaged position of the header. Consequentlythe tumbler drum cannot be put into driven condition while the shelldoor remains open. on the other hand,. when the shell door is closed andthe operatinglever 89 is in its rearwardor header engaged position, theprojection 96 of the interlocking member lies in the path of anotherportion of the camlike abutment I23, making it impossible to open theshell door. This arrangement thus makes it impossible, once' the dryingcycle has started, to introduce goods freshly laden with solvent andthus upset the control of the air-vapor mixture within the tumbler, avery necessary safety precaution.

Now,'since, as will be shown hereinafter, it, is impossible that thestarting lever 89 be put into engagement position unless current isbeing supplied to the electric control devices, hereinafter referred to,which first necessitates initiating operation of the fan by supplyingsteam to the steam turbine, it follows that the dryer cylinder cannot beset in operation until after the fan is started.

As will be explained in connection with the wiring diagram, the mainelectric line through the magnetic starter includes a switch R which ismounted upon the back sheet of the tumbler casing, see Fig. 3, and whichis preferably a tilting mercury switch adapted to prepare the magneticstarter circuit so that, after the switch R is closed. the said circuitbecomes' manually operable when the fan is in operation. This resultsfrom the fact that when the fan is in operation the unbalanced damper 29will be moved by the air stream from the fan, from its normal shut-01fposition closing off the discharge duct, to an open position which willnot interfere with the air discharged from the fan. In the closedposition of the damper the switch R is open, and in the open position ofthe damper the switch R is closed. Thus switch R is provided in thestarting circuit for the control mechanism in order to be assured thatthe turbine is started when the steam is admitted to the same and thatthe fan is in operating condition.

Safety devices operable upon failure of steam to the fan turbineSupported upon the bed plate 90, see Fig. 3,

' is a solenoid I25 to the core of which is attached a weight I26 ofsuflicient mass to cause the immediate descent of the solenoid corewhenever excitation ceases. As will be more fully explained inconnection with the wiring diagram,

this solenoid is energized under normal working conditions upon theclosing of the magnetic starter, which is indicated inthe drawings bythe letters MSand which is shown located on the tumbler housing in Figs.1 and 3. It should be' understood that operation of the magnetic startercloses the main switch which controls operation of the automatic cyclecontrol devices and that the solenoid I25 remains energized as long asthe main switch in the magnetic starter remains latch I21 having an armI21" maintained by gravity in engagement with a shoulder I26 on thesolenoid weight I26 and having another hookshaped arm adapted tocooperate with the interlock 96 to prevent operating lever 89 beingthrown'to engaged position unless solenoid I has been energized which,as said above, can only occur if the tumbler fan is in-operation and, aswill be shown hereinafter, if the temperature of the air entering thetumbler'from the heater is below a predetermined maximum. Thus it willbe understood that latch I21 serves as an interlock against improperoperation of the tumbler. When electric power is off, the solenoid I25being de-energized permits the latch to swing into interlockingrelationship with projection 96 so that, if the operating lever 89 be inthe disengaged position, it will be impossible to throw it to theengaged position. Should it happen that the lever 89 being in engagedposition and failure of current occur, the dropping of the solenoidweight will cause the latch hook to rest against the outer edge of theprojection 96 so that as lever 89 is thrown to disengaged position, asit must be to continue further drying operations, for

reasons which will appear later, the latch hook dropping underprojection 96 interlocks therewith and prevents further operation oflever 89 until current has been restored.

Also pivotally mounted on the bed-plate an adjacent the solenoid is alatch I28 which functions only upon failure of current to preventopening of the shell door I3 until current has been restored, which, ashas been pointed out, can only be after the temperature of the airentering the tumbler from the heater falls below a predeterminedmaximum. Latch I28 cooperates at one. end with a shoulder I26 on thesolenoid weight I 26, and at the other end is provided with a hook forinterlocking action with a coacting abutment member I23 movable with themember I 23 about the door hinge axis. When current fails, the droppingof the solenoid core, which has been holding the latch I28 out ofengagement with door member I23, now permits latch I28 to swing underthe action of gravity so as to interlock with the door member andpreventopening the door until current is restored. This latch neverserves to prevent closing the door.

, Thus it will be understood that irrespective of the period inthedrying cycle that current failure may occur,'the drying tumbler will beput out of operation and/or held out of operation until after current'isonce more flowing through the main switch. to the control devices, whichnecessitates that the fan'be in operation. Another safety elementrelated to the solenoid I25 is a switch K which will-be referred tohereinafter when its function will be explained in connecsolventremaining in theclothes. after centrifugal, extraction is evaporated anddriven off from the batch in the dryer drum. A' high heat period and acooling period have been mentioned and have been found to beadvantageous in carryas electrically operated timers, a magnetic switchcontactor, and certain other switches not hereinbefore mentioned.

The magnetic starter MS has been mentioned,

to terminate the low heat period of operation,

and operates again to terminate the high heat 'period of operation.After its second operation the half-turn motor will have returned to itsinitial position and be maintained in condition to tion-of the half-tummotor and the timersLHT;

andHHT need nothere'be repeated since these are fully described in theaforesaid patent,

Win'ng' diagram v I Again referring to Fig. 8, the wiring diagram willbe seen to embrace the various pieces of equipment heretofore mentioned.It comprises the single pole double throw switch A mentioned above asassociated in operation with the header operating lever 89, the singlepole double throw switch 3 operated by the half-turn motor, the

two electric timers, the solenoid I25, the halfturn motor P, the fanactuated switch R, a thermostatic switch F which is controlledby thetemperature of the air entering the tumbler from the heater, a magneticcontactor J interlocking center circuits; a single pole single throwmanually operated selector switch M, and a single pole single throwswitch K operated by the solenoid I25.

may not easily be tampered with. Mounted on top of this box are threepilot lights which indicate certain stages of the cyclic operation ofthe apparatus, but which will not be referred to again in thisspecification.

The thermostatic control switch F is operated by a suitable bulb I64,located in' the air passage leading irom the heater to the interior ofthe tumbler housing at a suitable location for nieasurmg the temperatureof the air after it has passed through both heater units and is about tobe brought in contact with the materials within the dryer drum.

Referring to the wiring diagram, LI and L2 indicate a single phase powerline entering the magnetic starter MS. It will be seen that the line LI,at a. point ahead of the magnetic starter, is connected by the switchcontact arm AI in the upper position thereof, through swfich contactsA2, A3 to the starting button, marked Start, of the magnetic starter.This connection only obtains when the header engaging lever 89 stands inits forward or disengaged position. Switch R, ,hereinbefore referred to,is located in a circuit between the stop button of the magnetic starterand the coil I66 of the starterso that, when the start button ispressed, a circuit to energize the coil I66 of this starter isestablished from line LI through switch A, throughthe start and stopbuttons of the magnetic starter, switch R, through the coil I66 to L2.Energization of the coil I66 will close the main switch contacts I61,I68 and thereafter the magnetic circuit is maintained by a jumper I69connecting LI into the starting circuit at a point between the start andstop buttons. Clos- '.ing the main switch contacts I61, I68 provides acircuit LIA, L2A to the control mechanism including the timers andhalf-turn motor P. The line LZA contains a suitable thermal element IIIfor overload protection.

It will beunderstood from what has been said that, tobegin operation ofthe tumbler, the

the magnetic starter MS which is preferably p'rovided with overload andlow voltage protection,

For economy in mechanical operation and wirr ing, switeh B' and otherswitches, not pertinent to the present invention, are enclosed in asingle switchbox I43, best seen in Fig. 5. Switches A and M are locatedin a single box I, see Figs. 1 and 3. Also three pieces of equipment,the low heat timer, magnetic contactor J and the thersuitable-box I63mounted upon the rear portion of the topof the tumbler housing. This boxis preferably equipped with a look, not shown, since the low heat timerand thermostatic switch F are mostatic switch F, are located togetherwithin a steam valve ,3I must be open, admitting live steam to theturbine. This starts the fan in operation and, as soon as a suitable airflow has been set up through the heater and tumbler,

movement of *the unbalanced damper 29 will close the switch R. It willbe understood at this time that the heater is under the control. of thethermostatic valve 43. It will be seen also that after the closing ofthe switch R and the The switch F is normally held in an open positionat temperatures above the selected temperature at which the apparatus isto operate during 'the low heat period, as, for instance; ,F. If, at thebeginning of a cycle. the temperature stands below or at 1 :0 F., theswitch F will be closed and a circuit will be completed from LIA throughswitch K, through the coil of the magnetic contactorJ and back to lineL2A. Thus the magnetic contactor will be energized and, drawing up itscore, will complete a circuit by way ofswitch contacts J3 and J4 throughthe coil of the solenoid I25 and will also complete a circuit by way ofmagnetic contacts J I and J2 through its own operating coil. Thus thesolenoid I25 will become energized and, by

the raising of its core, open the circuit through the switch K, so thatthereafter the coil of the magnetic contactor -J is maintained in anenergized condition solely through the maintaining circuit including-thecontacts, JI, J2.

Referring to Fig. 3 will show the switch K as located closely adjacentthe solenoid I25 upon the side of the tumbler housing. The solenoidweight I25 is provided with a shoulder I26 having a cammingsurface forengaging roller I14 carried by a lever I12 pivotally supported at I13 onthe box of the switch K. This lever is provided with an adjustable boltI15 adapted to engage the push button KI of the normally closed switchK. This switch is merely a, push button switch of a 'well known typebiased normally to closed circuit condition. When the,

solenoid is engaged, the engagement of the adjustable bolt with the pushbutton KI opens the circuit through switch K, which no longer is neededsince the magnetic contactor J is now self-maintained, as mentionedabove.

It will be remembered that-with the solenoid Low heat period ofoperation As previously explained, when the operating lever 89 isthrownto start the drying cycle, this operates switch A through roller92 and operating arm 93, causing the contacts A2, A3 to be broken, andthe contacts A4, A5 to be made.

- Thus a live circuit. is established to the switch '3 if the selectorswitch M is closed. This sebrush P2 passes fromthe segment P4 to thesegment P5, the motor is connected directly in circuit with line LIA sothat for the rest of its half-revolution the motor is energized from LIAthrough the motor coils and back to HA. At the end of thehalf-revolution the brush moves ofl' segment P5 onto segment P6 which atthis time is not connected with the line LI The half-tum motoraccordingly stops at thispoint.

High heat period of operation When the half-tum motor thus makes itshalirevolution, it starts the high heat period of the drying cycle byopening valve 38 and admitting live steam to 0011 20 of the secondaryheater I1. It also operates switch B, as will be explained hereinafter.Thus the secondary heater, which up to this time has received no steamfrom any source, now receives steam to its coil 20 directly through themechanically operated valve 38. The flow of steam in the exhaust lineleading to the coil I9 of the primary heater I6 has, as was said above,been under the control of the thermostatic valve 43. The thermostaticvalve will continue to operate so long as the temperature existing inthe measuring chamber 2I does not exceed the predetermined temperatureof the low heat period so that, after the operation of the mechanicallyoperated valve, the primary heater receives whatever steam is passed bythe thermostatic valve while the secondary heater becomes highly heatedby the high pressure steam now passing through its coils. When thehalf-turn motor operated to change from low heat to high heat period, itoperated switch B to break contacts B4, B5 and make contacts B2, 133.

When the live circuit through B4, B5 was broken, the low heat timer wastie-energized and,

' through spring action, the timer was automatilector switch'M is, asnoted above, located in' the same switch box I with the switch A, but ismanually operated and is only opened when drying certain types ofgarments adversely affected by high temperatures. understood that withthe switch M open, the apparatus will not operate through the differentstages of the drying cycle, but may be operated for an indefinite periodof time under the conditions of the low heat period, with thetemperature maintained at thetemperature for which the thermostaticvalve 43 is set. 5

Assuming, therefore, that the switch in is closed, the live circuitcontinues through contacts B4, B5 of switch B, to the low heat timer LHTby means of a line I18, and through the timer-back to line L2A by meansof wire I11. Thus the low heat timer is set in peration concurrently w hthe throwing of the operating lever as. Having established previously bytest that the low heat 'period shall be, say, ten minutes, after tenminutes have elapsed from-the throwing of the oper-;

It will be readily cally reset to zero ready for the beginning ofanother cycle. The wire I19 now being alive through closure of switchcontacts B2, B3, current flows to the high heat timer HHT starting thelatter to control the period of high heat operation. After a time, thedetermination of which has been established by test, switch D in thehigh heat timer is closed completing a circuit through wire I" tocontact P6 of the half-turn motor which becomes energized and makes asecond half-revolution back toits original position and, in so doing,closes the valve 38 thus cutting off the steam supply to the secondaryheater. This restores the steam control to the condition desired duringthe ensuing cooling period and at the beginning of the next dryingcycle. This reversal of the halftu'mmotor from high hea to low heat isthe bebinning of the final or c The second half-revolution of thehalf-turn motor shifts the contact member BI of switch B, breaks thecircuit between B2 and B3, I and reconnects contacts B4 and 35. Thus.the high heat timer is de-energized and returns to zero position. Duringthe high heat period or operation, the temperature of the air passingthrough the tumbler may be carried well above 200 F. because by thistime only a small amount of solvent remains in the clothing and it isthus impossible to develop an explosive mixture in the drier.

If for any reason the header enga in lever be thrown to its disengagedposition during the low heat period, the low heat timer will imme- Idiately be thrown outof action and will return to its initial position.Also, lithe lever I! be mam; to diseng ed position during the high heatDe; riod, switch contact AI, by bridging contacts A2,

period of the cycle.

Cooling period of operation Under some conditions the cycle ofoperations might terminate here, but it has been found in practice thatthe time usually consumed to unload and reload the tumbler isinsufiicient to cool the tumbler to a temperature below the flash-pointof high heat to the cooling stage. The thermostatic valve 43 may or maynot be open when live steam is being supplied to the secondary heater,depending upon the temperature existing in themeasuring chamber 2I.

It should be noted that the steamvalve 40 is included in the pipingsystem only as a manual means for admitting live steam to the tumbler atthe beginning of the operating cycle. This is done to make the operationof the tumbler conform,

' if found desirable, to a long established practice the solvent, thatis, below themaximum temperature established for the low 'heat period.It has been found desirable, therefore, in order to secure completesafety, to introduc a cooling period immediately succeeding the highheat period in order that the temperature of the ,air entering the dryermay reduce to the temperature set- .(ting of the thermostatic switch F;

During the cooling period a reduction of the temperature of the airentering the drum takes place, since the secondary heater is nolongeroperative. When the temperature is lowered to the setting of thethermostatic switch F, this switch closes and the apparatus is ready tobegin a new cycle, after. the operator has thrown his operating lever todisengaged position, opened the tumbler door, and replaced the load inthe turnbler drum with a fresh load requiring drying. I

As said above, switch B is actuat'ed by the halfturn motor P. The-switchB is a shiftable switch contained in the box I43 located adjacent thehalf-turn motor P at the top of the tumbler. Mounted-on an extension ofthe half-tum motor shaft P2 is a cam IBI mounted on a shaft I83.Suitably supported in theframework of the motor" assembly is anoperating'arm I84. At one end, arm I84 is equipped witharoller I86contacting cam I8I and at the other end with an adjustable stud I81contacting a push button of the switch B located in the switch box I43.Thus the cam I8I elevates the roller I86 and depresses the other end ofthe operating arm I8}! when, at the end of the low heat period, thehalf-turn motor makes its first half-revolution, thus depressing thebutton of switch, B and changin switch from its low heat position to itshigh heat position and, when .the half-turn motor makes its/secondhalf-revolution to change the tumbler fr m the condition for highheat-to the condition for cooling, the said cam moves the operating armI84 to permit restoration of switch B to its original position withcontacts B4, .85 made and contacts B2, B3 broken. A more completedisclosure and description of the timers, the halftum motor, and thesaid cam operating mechanism for'switch B as well as for certain signalcontrolling switches, omitted herein, may be had by reference to thesaid Patent 2,203,422.

In the operation of the tumbler the main shutoff valve 3| is manuallyoperated and is used only to turn on or shut off the steam supply to Ithe tumbler and to the stream turbine. The lever operated valve 38 is edby the half-turn motor every time th automatic drying cycle changes fromlow heat to high heatconditions, and is closed again when the half-tummotor is called upon to change the tumbler operation from of somecleaners, by admitting steam for a few moments at the beginning of the.operating cycle to prevent the accumulation of an abnormal amountofstatic electricity, a condition which might develop when drying suchmaterial as silk, particularly in cold weather.

It will be noted from the above that from the present construction areeliminatedall devices for supplying steam to the interior of the tumbleror blowing a whistle in the event of current failure since, with a fandriven b a steam turbine, current failure would have no effect upon theflow of aii th'rough the tumblenunless simultaneously there were failureof steam as well. Live steam at a sufficiently high pressure forefficient operation of the turbine, say'90 pounds to the square inch,will provide exhaust steam at a suitable temperature to maintain the airleaving the primary heater at the desired temperature below flash-point.Should there be any excess of steam in the exhaust line so as to raisethe temperature of the thermostatic valve to the closing point of saidvalve, the excess of pressure in the exhaust steam line will be takencare of b the back pressure valve3'l which, as was pointed out above, islocated in the turbine exhaust line beyond the connection of that linewith the thermostatic valve 43. The surplus, of exhaust steam may beused for any low pressure accomplishment. Should there be a failure ofsteam to the ually cool permitting the operatorto remov the batch ornot, as he might desire. However, since with the opening of the switch Rthe solenoid I25 would be de-energized, although it would be possible tomove the operating lever 89 to its disengaged position and stop rotationof the tumbler, it wouldnot be possible to raise the tumbler door I3until current is again restored to the solenoid I25 and, as said above,this could not take place until the temperature within the tumbler fallsto a point permitting the closing of the switch F."

As many possible embodiments may be made of the above invention withoutdeparting from the scope thereof, it is to be understood that all matterherein set forth or shown in the accomtions, a fan driven independentlyof said cylinder driving means for moving a current of air through saidtumbler, an electric circuit including circuit controlling meansoperatively res portsive to the passage of air through said fan, andelectric means interconnected with said circuit cooperative with saidoperating means for said control means to prevent starting cylinderrotation unless said circuit control means isfunctioning to energizesaid circuit.

2. In apparatus of the character set forth, in

combination, a tumbler housing, a rotatable cylinder in said housing,driving means for said cylinder operatively connected with a source ofpower, control means for said driving means,

means for operating said control means having cylinder operative andcylinder inoperative positions, a driven fan operated by power fromasource independent of the sourceof power for said cylinder drive formoving a current of air through said tumbler, a-movable member locatedin the air stream of said fan, an electric circuit including circuitcontrolling means operable by said movable member, and electric means insaid circuit cooperative with said operating means for said controlmeans to prevent starting cylinconnection, means connecting saidsecondary heater with said steam supply connection, and meansindependent of each other for controlling the steam supply to therespective heaters.

4. In apparatus of the character described, in combination, a dryingchamber, steam driven means having relatively high and low pressuresteam supply and exhaust connections, a fan driven by said steam drivenmeans for causing a current of air to pass through said drying chamber,heating means for said air comprising a primary heater and a secondaryheater, means connecting said primary heater with said exhaustconnection, means including a control valve connecting said secondary.heater with said steam supply connection, and time controlled operatingmeans for said control valve.

5. In apparatus of the character described, in

combination, a drying chamber, steam driven means having relatively highand low pressure steam supply and exhaust connections, a fan driven bysaid steam driven means for causing a current of air to pass throughsaid drying chamber, heating means for said air comprising a primaryheater and a secondary heater, means connecting said primary heater withsaid exhaust connection, means connecting said secondary heater withsaid steam supply connection, means for controlling the steam supply tosaid secondary heater, an electric circuit including automatic devicesto effect operation of said controlling means, a movable member locatedin the air stream of said fan and movable by said air stream, and meansin said electric circuit operable by said movable member to renderinoperative said electric circuit and included automatic devices.

, WILLIAM STROBRIDGE.

